Basic Research
- what is being studied?
- research goal?
- examples?
- Cells, tissues, and animals in laboratory settings
- understanding disease mechanisms and the effects of toxic substances
- toxicology, immunology
clinical research
- what is being studied?
- research goal?
- examples?
Sick patients who come to healthcare facilities
Improving diagnosis and treatment of disease
Internal medicine, peds
Public health research
- what is being studied?
- research goal?
- examples?
- Populations or communities at large
- Prevention of disease, promotion of health
- epidemiology, environmental health science
what are the two basic assumptions of epidemiology?
- Human disease does not occur at random; there are factors or determinants that can increase or decrease the likelihood of disease
- The factors or determinants (some casual and some preventative) can be identified by systematic investigation of populations or subgroups within populations
define epidemiology
The study of the distribution and determinants of disease frequency in human populations and the applications of this study to control health problems
what are the objectives of epidemiology?
- Study the natural course of the disease
- Determine the extent of the disease within a population
- Identify patterns and trends in disease occurrence
- Identify the causes of disease
- Evaluate the effectiveness of measures that prevent and treat disease
What is the sequence of epidemiologic investigations?
- Suspect that exposure influences disease occurrence
- Form hypothesis
(First two are descriptive ) - Conduct epidemiological studies to measure the relationship between exposure and disease
- Judge whether the association is valid, and causal, considering that:
=Accumulated evidence /Bias/Positive and negatives of study design - evaluate preventions and treatments
(Last three analytic )
who was William Farr?
- when and where?
- what he do?
- mid-1800s in Great Britain
- combined registration data on births, marriages, and deaths (numerator data) with census data on the population size (denominator data).
- data was accurate and complete
- Devised a categorization system for the causes of death so that the data could be reduced to a usable form
- Made contributions to the analysis of data, including the invention of the standardized mortality rate
Ricard Doll and A. Bradford Hill
when and where?
- research on?
- what did their work do?
- Place: England and Wales/After World War 1B( 20th cnetury)
- Conducted early research on smoking and lung cancer
- Their work created a shift from research from infectious to chronic disease. This was fueled by the idea that chronic disease was not just a degenerative disorder of old age but a potentially preventable disease with environmental origins.
Thomas Dawber and William Kanne
- when and where?
- what did they do?
- The Framingham Study which was one of the most influential and longest-running studies of heart disease
- 1948 in Framingham Massachusetts
John graunt
- when and where?
- what was he considered the first at?
- what did he do?
- 17th century London
- epidemiologist, statistician and demographer who published Natural and Political Observations Mentioned in the Following Index, and analyzed the Bills of Mortality in 1662
- He had discovered the numerical regularity of deaths and births, sex rations, and proportions of deaths from certain causes
- made first mortality table
- developed early census
James lind
- mid -1700s - in navy
-Demonstrated that experiments could be used to test hypotheses; conducted an experimental study on treatment of scurvy - He compared two groups of individuals (experimental and control) and actively manipulated factors to study (what they ate on the ship)
John Snow
- Place: London and Paris/1800s
- Conducted groundbreaking work to demonstrate that cholera was a waterborne infectious disease before the discovery of the pathogen
what is descriptive?
- What are the key characteristics and purposes of descriptive epidemiology? -
- which types of studies are commonly used?
- Descriptive - describes disease patterns
- To monitor public health
- Evaluate the success of intervention programs
- To generate hypotheses about the causes of disease
- Which leads to identifying and counting cases of disease in populations and conducting simple studies
- Case report, case series, cross-sectional study, ecologic study
What is analytic/scientific ?
- search for disease causes and prevention
- To evaluate hypotheses about causes of disease and to evaluate the success of intervention programs
- This leads to comparing groups and systematically determining if there is an association
- Clinical trials, experimental study, case-control study
Streptomycin tuberculosis trails
- who contributed?
- outcomes of interest? (dependent)
- exposure (independent)?
- what was the study?
- How did the study impact science
- British Medical Research Council (MRC)
- dependent: Death rate, improvements in TB symptoms
- independent: Streptomycin treatment
- designed to assess the effectiveness of streptomycin in halting the progression of TB in patients
impact
- introduction of randomization - minimized bias and ensured more reliable outcome
- objective data collection: used precisely and objective endpoints
- Ethical Considerations by not giving treatment to some patients
- restricting the types of patients eligible for the trial and ensuring random selection, the trial established standards for future clinical trials.
studies in smoking and lung cancer
- who contributed?
- outcomes of interest? (dependent)
- exposure (independent)?
- what was the study?
- How did the study impact science
- Richard Doll and A. Bradford Hill
- dependent: Lung cancer incidence and mortality rates
- independent: cigarette smoking
- Case-Control Study (1950): Doll and Hill compared 709 lung cancer patients with 709 controls, finding significantly more smokers among lung cancer patients, suggesting smoking as a major risk factor.
- Prospective Study (1951): They surveyed 59,600 British doctors, tracking smoking habits over time to study its health impacts, including lung cancer, and found that quitting smoking reduced the risk of disease.
- shift from Infectious to Chronic Disease Research
- foundation for Modern Epidemiology: The methods they employed—case-control and cohort studies—became standard approaches in epidemiology for studying the causes of chronic diseases.
- Smoking Causality - even though they did not identify carcinogens they understood that it was preventable
- work influenced the design of future epidemiological studies, emphasizing the need for large sample sizes and long-term observation to understand the impacts of behavioral changes on health.
Framingham study
- who?
- dependent?
- independent?
- what was this?
- contribution?
- Thomas Dawber and William Kannel
- d: Cardiovascular disease incidence, Mortality rates
- I: Risk factors for cardiovascular disease:
- The Framingham Study began in 1947 with the goal of identifying early markers of cardiovascular disease in a healthy population. Over time, the study expanded to investigate the causes of cardiovascular disease
- identification of risk factors
- shift to non-infectious Disease Research to preventable diseases
- Model for Cohort Studies - influencing the design and methodology for studying chronic diseases
- he findings led to public health campaigns and medical interventions aimed at reducing cardiovascular risk factor
Describe the five key words/phrases used in epidemiologist definition
- population is defined as a group of people with common characteristics
- Disease frequency - quantifying how often a disease arises in a population
- Distribution the analysis of disease patterns according to the characteristics of person, place, and time (who is getting the disease, where is it occurring, and how is it
changing over time) - Determinants are the factors that cause some people to get the disease. Factors that prevent some people from getting the disease (exposure)
- factors that bring about change in a person’s health or make a
difference in a person’s health. - Disease control: accomplished through epidemiological research, and through surveillance
efforts. Attempting to control health problems in populations
